1. Field of the Invention
The present invention relates to a device driver for controlling a plurality of hardware units connected to a computer system and controlled by different methods, a control method for device drivers and a computer-readable medium for storing a control program for device drivers.
2. Description of the Related Art
A conventional device driver controls a plurality of hardware units connected to it either in accordance with programs each intended for one or another of these units, or in such a manner that, as disclosed in the Japanese Patent Application Laid-open No. 4-58351, the segment which does not depend on the type of hardware is made independent as standard processing and processing intrinsic to each unit of hardware is performed in accordance with a program incorporated as a built-in subroutine.
Therefore, a problem associated with the first cited prior art method is that, where a plurality of peripheral units controllable by different methods are to be connected to a single computer system, as many device drivers as the control methods are required. A problem associated with second cited method is that, every time the device driver needs to support a new type of hardware, a subroutine for that particular hardware unit should be added, resulting in an expansion of the device driver and a consequent increase in the memory capacity it occupies.